1. Statement of the Technical Field
The present invention relates to the customization of a host application graphical user interface (GUI) and more particularly to the rapid and efficient GUI refacing of a legacy application.
2. Description of the Related Art
Customizing the GUI of a legacy application has proven a tedious task. In most cases, an integrated development environment (IDE) or design studio is required to effectively generate a GUI based upon the original display screens of the legacy application. During the refacing process, each screen of the legacy application must be marked up individually. Even where legacy application screens can be structured into a handful of repeatable layout patterns, the GUI must be redrawn from scratch, screen by screen. Hence, the conventional refacing of a legacy application can be time consuming and can result in interface inconsistencies. Also, the process of conventionally refacing the GUI of a legacy application can be inflexible thus hindering the ability both to extend the GUI with additional functionality and also to migrate the GUI to other platforms.
In an effort to overcome the clear deficiencies of conventional legacy application GUI refacing, some have developed template based customization and component extraction techniques in an effort to improve the screen marking experience. Still, template based customization and component extraction techniques remain tied to screen flows and require screen level drawing. An experienced legacy application IT specialist or architect has not a rapid and efficient method for dynamically and systematically generating GUIs from multiple fixed patterns.
Yet others have proposed template formats configured to manually specify multiple default GUI styles. Examples include the use of pre-scripted extensible stylesheet (XSL) transformations designed to process the presentation layer for legacy hosts. Nevertheless, the stylesheet creation process itself has proven to be a time consuming process. Also, when using XSL transformations, presentation styles, screen patterns, and the meaning of the underlying content are not automatically associated. While global customization can be applied to partially overcome this problem by pre-configuring global changes for all screens, global customization remains merely a partial solution applying only to trivial patterns.
In view of newer technologies such as Java™ server pages (JSP), the extensible markup language (XML) and XSLT, meta-data has become an obvious template technique useful in describing GUI transformations for legacy application screen data. In particular, newer technologies such as JSP, XML and XSLT can be effective in producing transformations for the individual screens of a legacy application. Notwithstanding, these newer technologies alone remain insufficient when systematically transforming a large number of display screens of a legacy application. Specifically, even with the newer transformation technologies, an application designer still must learn the template formats including syntax and semantics, match screen patterns manually, create individual GUI elements, associate the legacy application screen contents with the individual GUI elements, and enforce the look-and-feel consistency of each screen.
Importantly, the template format both old and new itself is not comprehensive enough to be extensible. Even if both the GUI element coordinates and GUI description are included as attributes in a template, the rules for constructing the GUI from the legacy application display screen region can be quite complex and the interpretation of the attributes seldom can be reflected by the template. In consequence, code modifications of the base processing can be required in a purely template driven technique. Therefore, the mere provision of an external template format is not sufficient for systematic GUI transformations of the display screens of a legacy application.